The heat transfer industry involves the processes of silk screening or direct printing in which a mesh is used to deposit printable ink onto a substrate. The substrate typically used in a direct printing procedure is a fabric or an end-user item such as a T-shirt. However, in heat transfer methods, the substrate is paper or any paper-related product. The printed paper can be applied to the fabric using an iron or iron-on machine. Traditional heat transfer methods started in the 1960s using a process called spot color in which each color was printed separately. This process was very basic and, because of the use of plastisol inks, resulted in bright colors. However, it was not a cost effective process and had limited applications.
In the early 1990s, a new process was introduced known as CMYK Puff Heat Transfer. This process utilizes a transfer base material, four-color (or CMYK) inks, and puff base material. In this process, the transfer base material is applied on the substrate or paper followed by the CMYK colors, which are printed separately in no particular order. Finally, the puff base material is applied. “Puff” is the standard term used in the industry to describe material having a high-raised textured finish. The advantage of this process is that many pantone colors can be achieved by printing only the four process colors. The final print will have velvet-like feel after application due to the application of the puff base material. There are, however, two major disadvantages of this process. The first disadvantage is that the colors tend to have a dull-looking finish without any bright colors, unlike the spot process. The reason for this is that the puff base material dilutes more than 30% of the intensity or the strength of the actual printed inks. The second disadvantage arises from the toxic ingredients that are used in the transfer base material. Traditionally, to produce a quality CMYK puff heat transfer, the percentage of the transfer base material by weight should not be less than 20%, otherwise the image will not transfer from the paper substrate to the applied product.
Transfer base material is typically comprised of 75% polyvinyl chloride, 15-17% diisodecyl phthalate, 5% adhesive and 3% other ingredients included vinyl acetate. According to the OSHA Regulation 29 CFR 1910.1017, vinyl chloride in its vapor form, is a potential cancer suspect agent. According to the Consumer Law Page website (http://consumerlawpage.com), polyvinyl chloride may cause cancer with a latency period of 15 to 40 years if it is inhaled in smoke form. According to OSHA regulation 29 CFR 1910.178, vinyl acetate may cause tuberculosis. Finally, according to the International Programme of Chemical Safety (“IPCS”), diisodecy phthalate is a substance that may have damaging effects on the liver.
Application of a heat transfer to a fabric using an iron-on machine at 400° F., produces vinyl chloride after the image is peeled off the paper, which, if inhaled directly by the applicant, may produce health problems. In a typical heat transfer facility, a user can perform approximately ten average-size transfers in a 15 minute period. A heat transfer that contains 20% of a transfer base material typically contains 15% polyvinyl chloride, 3% diisodecy phthalate and portions of vinyl acetate. The ten transfers contain a total of approximately 1 gram of vinyl chloride in a vapor form concentration of 9.8 ppm, which exceeds OSHA regulation 1910.1017(c)(2) by 4.8 ppm. In order for a user to avoid the possibility of inhaling carcinogens or other related hazardous fumes, the vinyl chloride concentration should be below 5 ppm, which means each transfer applied should not contain more than 8% of polyvinyl chloride. Therefore, the heat transfer process should not have more than 10% of transfer base material. Tables 1 and 2, in the Detailed Description section below, illustrate this in terms of CMYK puff heat transfer composition and the concentration of the vapor form of vinyl chloride.
The present invention improves upon the traditional heat transfer process by using a limited and specific amount of an improved transfer base material that fully complies with OSHA regulations and results in an improved heat transfer material that glows in the dark for safer and more decorative characteristics.